Influence of the Polypyridyl (pp) Ligand Size on the DNA Binding Properties, Cytotoxicity and Cellular Uptake of Organoruthenium(II) Complexes of the Type [(η⁶‐C₆Me₆)Ru(L)(pp)]ⁿ⁺ [L = Cl, n = 1; L = (NH₂)₂CS, n = 2]

Abstract

The DNA binding of polypyridyl (pp) (η 6 -hexamethylbenzene)ruthenium(II) complexes of the type [(η 6 -C 6 Me 6 )-RuCl(pp)](CF 3 SO 3 ) (pp = phen, tap, dpq, dppz, dppn) 1-5 and [(η 6 -C 6 Me 6 )Ru{(NH 2 ) 2 CS}(pp)](CF 3 SO 3 ) 2 (pp = dpq, dppz, dppn) 6-8 has been studied by UV/Vis spectroscopy, circular dichroism and viscosity measurements. Complexes 3-5, 7 and 8 are potent cytotoxic agents towards the human cancer cell lines MCF-7 and HT-29. Stable intercalative binding into CT DNA is indicated for the dpq and dppz complexes by large increases ∆T m of 12-25°C in the DNA thermal denaturation temperature for r = [complex]/[DNA] = 0.1. Large viscosity increases for DNA in the presence of 3 and 4 are also in accordance with this binding mode as are the pronounced hypochromic UV/Vis shifts for the π-π* transitions of the dppz ligands of 4 and 7 in the range 360-400 nm. A small ∆T m value of 2°C and effectively unchanged vis-

Small cationic antimicrobial peptides delocalize peripheral membrane proteins

“…To this end, cells were harvested and washed five times with 100 mM Tris/1 mM EDTA before ultrasonication, centrifugation, and ultracentrifugation. Ruthenium contents were quantified using a Vario 6 graphite furnace atomic absorption spectrometer (Analytik Jena) as described previously (82)(83)(84).…”

Quantifizierung der Zellaufnahme metallierter Peptide und Peptidnucleinsäuren durch Atomabsorptionsspektroskopie

“…[13,26] Wie wir bereits früher berichteten, wird die Zellaufnahme von metallhaltigen Wirkstoffen erheblich durch die Eigenschaften des Liganden und die Ladung des Zentralatoms beeinflusst. [27] Wir interpretieren die relativ niedrige Aufnahme der hier untersuchten Verbindungen als eine Folge der hydrophilen Natur der Peptide. Andererseits kann erwartet werden, dass die Cobaltkomplexe nach Verdrängung der Nitratliganden durch Wasser positiv geladen vorliegen.…”

Substitution of Metallocenes with [2.2]Paracyclophane to Enable Confocal Microscopy Imaging in Living Cells

“…[30] In short, HT-29 colon carcinoma cells were grown until at least 75-80 % confluency in 75 cm 2 cell-culture flasks. Stock solutions of the compounds in DMF were prepared and diluted with cell culture medium to a final concentration of 5.0 μM immediately before use (final DMF concentration: 0.1 % v/v).…”

“…Probes were injected (25 μL) into coated standard graphite tubes (Analytik Jena AG) and thermally processed, as described previously with minor modifications (see oven program in Table S3). [30] Ruthenium was quantified at a wavelength of 349.90 nm. The mean integrated absorbance of triple injections was used throughout the studies.…”